Agreeing with a previous unnamed poster –
It dawned on me one day, that the old advice of cutting a notch in the end of the nail, made little sense – since the nail is an arch from start to end…the strategic way to weaken that arch, (and thereby relieve the pressure), is to thin about a 1/4 – 1/3 inch strip of the middle of the entire (hardened) nail, and this is most easily accomplished with a small file.
Taking care not to file all the way through…but rather about half way through the thickness of the nail.
This weakens the arch, and allows the edges of the nail to ‘lift’ (and relieve that downward pressure) much more easily, than trying to pry up the edges of a nail which is a stongly formed arch…usually after careful filing of the middle strip, no manual, mechanical lifting of the edges is even necessary – they are alleviated by the weakened arch of the nail itself.
File a narrow strip from just in front of where the nail begins – straight, all the way to the tip of the nail. Evenly removing approxiametely 1/2 the thickness of the nail.
If top of filed nail rubs inside footware, pad with small piece of gauze , etc.